require 'net/http'
require 'rexml/document'

# Pure ruby wrappers for TLC (http://www.tlcdelivers.com) web services
# Author::    Justin Duewel-Zahniser  (mailto:justin@justindz.org)
# Copyright:: Copyright (c) 2006 Justin Duewel-Zahniser
# License::   Distributes under the same terms as Ruby

module TLC

	# The LibrarySolution class represents programmatic access to a
	# TLC Library.Solution v3.3.5 OPAC.
	# The new method takes two arguments:
	# * the web server domain - default "demo.tlcdelivers.com"
	# * the configuration name - default "pac"
	# e.g. - ls = TLC::LibrarySolution.new('demo.tlcdelivers.com', 'pac')

	class LibrarySolution
		attr_accessor(:web_server_address, :config)
		attr_reader(:availability_url, :availability_rn_url, :detail_url)
	
		def initialize(web_server_address='demo.tlcdelivers.com', config='pac')
			@avail_url = "/TLCScripts/interpac.dll?GetAvailability&IdList="
			@detail_url = "/TLCScripts/interpac.dll?LabelDisplay&config=pac&recordnumber="
			@web_server_address = web_server_address
			@config = config
		end
		
		# This method returns the raw XML for a request as a REXML::Document.
		# It takes three parameters:
		# * ids - either an ISBN or recordnumber or an array of ISBNs or recordnumbers
		# * type - :isbn or :rn
		# * detail - 0, 1 (default) or 2--you are unlikely to need to specify this
		# The &curbranch=Mail (e.g.) option is not currently supported.
		def get_avail(ids, type, detail=1)
			if ids.class == Array
				if type == :isbn
					ids.each_with_index do |isbn, i|
						ids[i] = clean(isbn)
					end
				end
				ids = ids.join(",")
			else
				if type == :isbn
					ids = clean(ids)
				end
			end
			qs = "#{@avail_url}#{ids}&detail=#{detail.to_s}" + if type == :isbn then "&type=isbn" else "" end
			
			xml = Net::HTTP.get(@web_server_address, qs)
			doc = REXML::Document.new(xml)
			return doc
		end
		
		# This method takes an ISBN and returns the internal recordnumber
		def get_recordnumber(isbn)
			return get_avail(isbn, :isbn, 0).root.elements['t'].attribute('rn')
		end
		
		# This method takes an ISBN and returns a URL to the title record display or nil
		def get_url(isbn)
			rn = get_recordnumber(isbn)
			if rn.nil?
				return nil
			else
				return "http://#{@web_server_address}#{@detail_url}#{rn.to_s}"
			end
		end
		
		# This method takes an ISBN and returns a formatted link to the title record display or nil
		def get_link(isbn)
			doc = get_avail(isbn, :isbn)
			rn = doc.root.elements['t'].attribute('rn')
			if rn.nil?
				return nil
			else
				ac = tc = 0
				doc.elements.each("r/t/lo") { |lo| ac += lo.attributes.get_attribute('ac').value.to_i ; tc += lo.attributes.get_attribute('tc').value.to_i }
				return "<a href=\"http://#{@web_server_address}#{@detail_url}#{rn.to_s}\">#{ac} of #{tc} available</a>"
			end
		end
		
		# This method takes an ISBN, checks the catalog for a matching record and returns true or false
		def has?(isbn)
			return !get_avail(isbn, :isbn, 0).root.elements['t'].attributes.get_attribute("rn").nil?
		end
		
		# This helper method just cleans up ISBNs
		def clean(isbn)
			isbn.gsub(/[^0-9X]/,'')
		end
	end
end